Symbiosis between methane-oxidizing bacteria and a deep-sea carnivorous cladorhizid sponge

Abstract

Dense bush-l~ke clumps of several hundred ~ n d ~ v l d u a l s of a new specles of Cladorhiza (Demosponglae, Poeciloscler~da) were observed near methane sources in mud volcanoes 4718 to 4943 m dcep In the Barbddos Trench The sponge tissue contalns 2 maln mo~pho log~ca l types of extracellular symbiotic bacteria small rod-shaped cells and larger cocco~d cells with stacked membranes Stdble carbon ~so tope values, the presence of methanol dehydrogenase and ultrastructural observatlons all lndlcate that at least some of the syrnblonts are methdnotrophic Ultrastructural e v ~ d e n c e of ~n l r ace l l~~ la r d ~ g e s t ~ o n of thp s y n ~ b ~ o n t s and the stable C and X values suggest that thc sponge obtalns a slgnlflcdnt portion of its nutr~tlon from the symbionts Ultrdstructure of the sponqe embryo suggests d ~ r e c t ransmission throuqh qc.neratlons In brooded embryos The sponge also ma~ntrilns a carnivorous feed~ng hdblt on tin swlmmlng prey, as do other cladorhlzlds K E Y L\/ORDS. Methanotrophy POI-~fera . Deep-sea . Symbiosis . Cold-seep communities